It's difficult to weave any thoughts I may have between the extended dialogue you've been having with Mr-B (Bi-located) so instead I thought I would just throw a few comments into the miscellany and see what happens.
Firstly I have no doubt that he experienced the same "oneness" that is at the core of most of my hallucinogenic experiences.
I have sympathy for his disorientation - It took me years to integrate what I know about both worlds.
I am aware that you can gain the notion of oneness but this is not the same as loosing yourself within it.
I find some people a bit dismissive about what I refer to as "Universal Consciousness" but I cannot stress enough that this is not merely a notion. I don't have any difficulty in accepting the reality of other peoples experiences however bizarre, yet I see all of these as being peripheral to the state of Universal Consciousness.
You refer to navigating those realms and this made it clearer to me how I see Universal Consciousness
I see it as the core experience - a state of nothingness from which all possibilities spring from. I use it as the central point of navigation - a point I always know I can get to. Increased familiarity with this point and how to get to it enables you to venture from it at your will - with complete control.
The result of this is that in my recent experiences with mushrooms and Salvia, over the last few years, fear is not an issue as it is simply somewhere I do not choose to go. Once you have faced the fear of death (not just the notion of it) and come out the other side there is not much else to be fearful of anyway!
I had been writing a piece on Universal Consciousness, intending it to be a guide to others, but recently I've realized that although the destination is universal we each have our own unique path. There is a real danger of getting lost by interpreting (or worse adopting) other peoples experiences on the way.
I do see the value of sharing your experiences - it's the reason we're here - but ultimately that is all they will be - your experiences.
I mention this because I sense in the later communications with Mr-B an element of mutual "defense of ones own corner".
Mainly this is regarding the pros and cons of exploring those other realms. Again we each have our own unique path and the decision to abstain from Salvia is ultimately his. I personally abstained from hallucinogens for over five years because reminding myself of the REALITY rendered daily life meaningless. I now like to be reminded as often as possible and view my use of hallucinogens as being wholly spiritual and almost entirely hedonistic.
Particularly fear should not be the primary reason for using Salvia!